Prosecutors on Thursday summoned a senior prosecutor who has come under public scrutiny over suspicious stock transactions.

Jin Kyung-joon appeared before the Seoul Central District Prosecutors' Office in southern Seoul to face questioning over the wealth he amassed through shares of Nexon Co., the country's leading online game maker.

"I admit to my wrongdoings and take it seriously," Jin told reporters before entering the prosecutors' office.

"I sincerely apologize for hiding the truth to cover my mistakes," he said. "I have already submitted a letter (to the prosecution) admitting to my faults and will tell everything based on facts during the interrogation today."

The case involving Jin came to light early this year as the senior prosecutor reported a whopping increase in his personal wealth in 2015. All ranking government officials and lawmakers are required to disclose changes in their personal wealth annually.

Nexon allegedly lent some 400 million won ($348,000) to Jin in 2005, helping the senior prosecutor to amass some 12 billion won of profits through stock transactions by 2015.

An ad hoc team investigating the case has been widening their probe, raiding the house of Jin, as well as the home and offices of Kim Jung-ju, founder of Nexon and incumbent chairman of its holding firm NXC Corp.

Kim was summoned Wednesday and grilled over allegations he helped Jin in return for favors, as well as other irregularities suspected to have been committed by his company.

The latest series of actions came within a week after the country's top prosecutor Kim Soo-nam launched the independent team to thoroughly investigate the case.

The special team can investigate without supervision, having only to report its results to the prosecutor general.

Jin offered to quit in April when the allegations arose, but the justice ministry has not accepted the resignation. (Yonhap)